Fertilizer use could reduce climate benefit of cellulosic biofuels

The use of nitrogen fertilizer on switchgrass crops can produce a sharp increase in emissions of nitrous oxide, a greenhouse gas up to 300 times more harmful than carbon dioxide and a significant driver of global climate change.

June 3, 2016 - Author: Layne Cameron

According to a new study from the Great Lakes Bioenergy Research Center and Michigan State University, the use of nitrogen fertilizer on switchgrass crops can produce a sharp increase in emissions of nitrous oxide, a greenhouse gas up to 300 times more harmful than carbon dioxide and a significant driver of global climate change.

Switchgrass is one of several crops poised to become a feedstock for the production of “cellulosic biofuels,” fuels derived from grasses, wood or the nonfood portion of plants. Though touted for being a clean energy alternative to both fossil fuels and corn ethanol, cellulosic biofuel comes with its share of complexities. Many of its environmental benefit depends, for starters, on how its crops are grown.

“We’ve established that the climate benefit of cellulosic biofuels is much greater and much more robust than people originally thought,” said Phil Robertson, University Distinguished Professor of Ecosystem Science at MSU and coauthor. “But what we’re also seeing is that much of that climate benefit is dependent. It’s dependent on factors such as land use history and – as we’re seeing with these results – it’s dependent on nitrogen fertilizer use.”